The paper by Robert S. Pindyck critically examines the use of Integrated Assessment Models (IAMs) in evaluating climate change policies and estimating the social cost of carbon (SCC). Pindyck argues that IAMs are flawed and largely ineffective for policy analysis due to arbitrary inputs, ad hoc descriptions of climate change impacts, and the inability to account for catastrophic outcomes. Key issues include the arbitrary choice of discount rates and social welfare functions, the lack of empirical foundation for climate sensitivity and damage functions, and the failure to consider the possibility of extreme climate events. Despite the extensive effort and resources invested in IAMs, Pindyck concludes that they provide little to no reliable information for policy decisions. He suggests that a simpler, more qualitative approach, focusing on plausible estimates of probabilities and impacts of catastrophic outcomes, might be more useful.The paper by Robert S. Pindyck critically examines the use of Integrated Assessment Models (IAMs) in evaluating climate change policies and estimating the social cost of carbon (SCC). Pindyck argues that IAMs are flawed and largely ineffective for policy analysis due to arbitrary inputs, ad hoc descriptions of climate change impacts, and the inability to account for catastrophic outcomes. Key issues include the arbitrary choice of discount rates and social welfare functions, the lack of empirical foundation for climate sensitivity and damage functions, and the failure to consider the possibility of extreme climate events. Despite the extensive effort and resources invested in IAMs, Pindyck concludes that they provide little to no reliable information for policy decisions. He suggests that a simpler, more qualitative approach, focusing on plausible estimates of probabilities and impacts of catastrophic outcomes, might be more useful.